STATE OF THE ART
The economic viability of a wave energy converter (WEC) depends largely on its power take-off system (PTO).
Active control of the power take-off is necessary in orderto maximise power capture across the wide range of sea-states encountered offshore and can also improve survivability.
As developer of an innovative design made of several modular components and, ultimately integrator of a complete marine energy WEC, Hydrocap has made its primary goal to design its SEACAP wec around the most reliable and efficient components, contributing to bring to market a new step change generation of PTO.
After analysis of numerous options, the solution retained has been a direct drive linear switched reluctance electric generator whose second generation is currently developped within SEA-TITAN, a H2020 funded project started earlier this year, in which Hydrocap is a collaborative partner, together with leading european actors of the electrical and marine energy sector.
The overall objective of SEA-TITAN aims at achieving high continuous peak force densities in order to significantly reduce the levelized cost of energy (LCOE) and also the capital expenditures (CAPEX), simultaneously increasing the float to wire efficiency (FtWE), defined as the ratio between the mechanical energy absorbed by the WEC and, the electricity output of the system.
Seacap is a “point absorber” system: a buoy absorbs the vertical motion of ocean waves; it floats around a column fixed to the seabed. The modular nature of the system emphasizes economy, performance, safety and reliability as well as survivability in extreme weather.
A scaled model of the device has been tested in a wave tank, confirming previous CFD yield calculations: in sea state conditions typical of the French Atlantic, the load factor achieved is 25%, which can be enhanced to 30% using a proprietary “latching” system.
Beyond the usual electricity production towards a shore base sub-station, the platform allows the on site conversion of this energy into “clean” hydrogen for new emerging market applications, particularly in the mobile sector (land and marine transportation).